Steam turbine apparatus



May 19 1931. K. FREY 1,806,065

STEAM TURBINE APPARATUS File d March 4, 1926 Patented May 19, 1931UNITE' STATES PAT NT-osmos- KARL FREY, OF ENNETBADEN, SVIITZERLAND,ASSIGNOR TO A. G. BROVJN BOVERI & CIR, OF BADEN, SWITZERLAND, AJOINT-STOCK COMPANY STEAM TURBINE APPARATUS I Application filed March 4,1926, Serial No. 92,309, and in Germany March 20, 1925.

This invention relates to the operation of back-pressure turbines, andhas to do with control of the exhaust pressure of the machine.

The general object of the invention is the provision of an arrangementwhich will control automatically the exhaust pressure conditions in suchfashion as to avoid power losses and overheating incident to operationof the turbine under low load.

Other objects will be indicated or pointed out hereinafter, or will beobvious toone skilled in the art upon an understanding of the presentdisclosure.

In the drawings forming a part of this specification I show indiagrammatic fashion certain embodiments of the invention, but the sameare presented for illustration only and are not to be regarded asexhaustive of JllQ structural forms the invention may take, or to beconstrued in any fashion to limit the appended claims short of the trueand most comprehensive scope of the invention in the art. In saitdrawings,

Fig. 1 is a diagrammatic representation of a sectional elevation of aturbine and control device, the scales of the two beingdisproportionate, and

Fig. 2 is a sectional elevation of an alter- 3 native arrangement of thecontrol device.

lVhen back-pressure turbines are run light the friction of the steam andthe consequent lost power and overheating become serious sources oftrouble, particularly when the hack-pressure is high. The purpose of thepresent invention is to avoid this serious disadvantage withoutaffecting the readiness of the turbine for immediate starting up.

According to the invention this is achieved by automaticallydisconnecting the turbine from the back-pressure pipe when running lightor with a small quantity of steam only, and allowing it to work with alower exhaust pressure. The exhaust may be to atmosphere or to acondensing apparatus if one is available. The change-over may beaccomplished in various ways by means of valves on the turbine itself orin the exhaust pipe.

Fig. 1 shows a possible arrangement for controlling a valve of thiskind. The valve casing a contains a disc valve 6 controlled by thepiston (Z through the valve stem 0. The space above the piston dcommunicates by means of a pipe 6 with the interior of the turbine T,preferably the first nozzle chamber 2?. When running with normal steamsup ply, the pressure on piston (Z' holds spring f compressed and valvedisc Z) in the lower po-' sition shown dotted, placing the exhaust pipe9 in communication with the back pressure connection it. Should thepressure in the admission chamber 6 fall consequent on the closing ofthe admission valve, the spring 7". beneath thepiston (Z isable to forcethe-disc b upwardsto the position shown, thus con necting the exhaustpipe 9 of the turbine to an auxiliary pipe i instead of to the backpressure pipe h. This auxiliary pipe'c ommunicates with thelowerpressure. When the pressure in the nozzle chamber again rises, thepiston (Z is forced down against the action of the spring f and the disc6 returns. to its normal position.

lVhen the turbine is governed by hydraulic means suchv as an oilpressure regulator of the well known type in which the pressure of oilin a servo line is varied incident to changes of the engine speed, thepiston (Z may, with advantage, be operated with the pressure oil, thechange-over of the exhaust from back pressure to atmosphere or lowerpressure he performed in the manner described above when the oilpressure in the servo systemfalls to a certain valueincident to decreasein load and steam admission to the engine.

iiccording to Fig. 2, the steam pressure in the nozzle chamber acts onthe piston controlling, by means of the small valve Z, the pressure oilwhich is supplied by pipe m and operates the piston d. The oil issupplied from the oil pump on the turbine. Various other arrangementsmay be utilized for effecting the operative connection. The invention,it will be observed, qualifies the turbine to control its ownback-pressure conditions so as to avoid interference from that source,with its effective operation.

What I claim is:

1. In apparatus of the character described, a fluid-pressure motorhaving a fluid-inlet and a fluid-outlet, means providing a plurality offluid passages, valve means operable to provide for selectivecommunication of said fluid outlet with said passages, and meansresponsive to high and low-pressure conditions at said fluid-inlet andbeing operable upon existence of such conditions to effect selectingaction of said Valve means.

2. In apparatus of the character described, a fluid-pressure motorhaving a fluid-inlet and a fluid-outlet, means providing a plurality offluid passages, valve means disposed for movement to a given positionand being operable thereat toprovide for communication between saidfluid-outlet and one of said passages and for movement to a differentposition and being operable thereat to provide for communication betweensaid fluidoutlet and another of said passages, and means responsive tohigh and low-pressure conditions at said fluid-inlet and being operableat such high-pressure condition to effect movement of said valve meansto said given position thereof and being operable at such low-pressurecondition to effect movementof said valve means to said differentposition thereof.

3. In combination with'a fluid motor having an inlet for the flow ofoperating fluid of varying pressures thereto, and an outlet for the flowof fluid therefrom, of a plurality of passages for the flow of fluidfrom said outlet, and means responsive to variations in pressures of theoperating fluid at said inlet for a selecting the passage for the flowof said fluid from said outlet. i

4. In combination with a fluid motor having an inlet for the flow ofoperating fluid of varying pressures thereto, and an outlet for the flowof said fluid therefrom, of a plurality of passages for the flow of saidfluid from said outlet, and means automatically operative responsive tovariations in pressure of said fluid at said inlet to selectively permitthe flow of said fluid from said outlet through said passages. V

In testimony whereof I have hereunto subscribed my name at Zurich,Switzerland on the 9th day of February, A. D. 1926.

KARL FREY.

